Folding ladders of the general type referred to are known in the art but these lack such attributes as light weight, inexpensive design and construction, and foldability into an easy-to-carry compact "package." The present invention furnishes these attributes in a novel manner, achieved mainly by the provision of symmetrical rails that complement each other in closed mode to house the rungs in what may be termed a closed shell. A further feature of the invention is the provision of a plurality of bearing blocks attached to and received within the C-shaped rails and providing pivots for the ends of the rungs. The pivots themselves are arranged so as to be flush with the outer surface of the respective rail, thus avoiding projections that could snag or hang up during use or carrying. Another feature is that end portions of the rails are so designed as to cooperate with each other during closed mode so as to complete the cylindrical shape from end to end of the folded structure. Still further, certain portions of the rails provide stops for certain of the rungs in the open mode of the ladder.
Further features and advantages of the invention will become apparent from the ensuing description and accompanying drawings.